Protective coat-forming coating composition, coated article, and multilayer laminate

ABSTRACT

A coating composition primarily comprising a disilane compound of the formula (A): 
 
X m R 1   3-m Si—Y—SiR 1   3-m X m   (A) 
 
wherein R 1  is a monovalent hydrocarbon group, Y is a divalent fluorinated organo group, X is a hydrolyzable group, and m is 1, 2 or 3, or a (partial) hydrolyzate thereof is applied and cured to form a protective coat having excellent chemical resistance and antireflection.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a 37 C.F.R. § 1.53(b) divisional of U.S.application Ser. No. 10/824,393 filed Apr. 15, 2004, which in turnclaims priority on Japanese Application No. 2003-113737 filed Apr. 18,2003. The entire contents of each of these applications is herebyincorporated by reference.

FIELD OF THE INVENTION

This invention relates to a protective coat-forming coating compositionprimarily comprising a fluorinated disilane compound of specificstructure and/or a (partial) hydrolyzate thereof, a coated articlehaving a protective coat formed by curing the coating composition, and amultilayer laminate.

BACKGROUND ART

Heretofore, fluoroplastics resistant to chemical attacks have been usedin the application where chemical resistance is required. Utilizingtheir inherent low refractive index, fluoroplastics are also employed inthe antireflection application as in displays. However, when thefluoroplastics are used as rubber or coating compositions, theirmolecular structure makes it difficult to form hard protective coatingshaving mar resistance.

Recently, hydrolyzable silane compounds having perfluoroalkyl groupswere developed. To take advantage of their favorable characteristics, avariety of coating compositions comprising hydrolyzable silane compoundshave been developed for imparting water repellency, oil repellency,anti-staining and anti-reflection. However, since perfluoroalkyl groupscontributing to these favorable characteristics are bulky and inert, thecured coatings have a low crosslinked density. As a result, the curedcoatings are fairly hard as compared with fluoroplastics, but still lackmar resistance.

Several systems were developed for enhanced mar resistance. For example,JP-A 2002-53805 describes co-hydrolysis of a perfluoroalkylgroup-containing silane and a silane compound such as atetraalkoxysilane; JP-B 6-29332 describes a system comprising aperfluoroalkyl group-containing silane, a disilane compound havingperfluoroalkylene as a spacer, and a tetraalkoxysilane; and JapanesePatent No. 2,629,813 describes a system comprising a disilane compoundhaving perfluoroalkylene as a spacer and an epoxy-functional silane.These systems achieve fairly satisfactory levels of desired propertiessuch as anti-staining, mar resistance, adhesion and antireflection.However, because of a reduced fluorine content, they lack chemicalresistance to such chemicals as household detergents. Especially thelack of alkali resistance is outstanding as the weak point ofpolysiloxane systems. This is problematic on practical use.

There are available no coating compositions that satisfy both marresistance sufficient to protect transparent substrates and practicallynecessary chemical resistance to household detergents used in cleaning.There are available no coating compositions that possess multiplefunctions of antireflection, anti-staining, water repellency and thelike as well.

SUMMARY OF THE INVENTION

An object of the invention is to provide a coating composition havingimproved chemical resistance and mar resistance and useful as aprotective coat on plastic substrates or the like; a coated articlehaving a cured coat thereof; and a multilayer laminate.

Making studies on coating compositions that satisfy both a substrateprotecting function in terms of mar resistance and a practicallynecessary level of chemical resistance, and optionally possess a surfacemodifying function of imparting antireflection, anti-staining, waterrepellency or the like, inventors have found that when a fluorinateddisilane compound of specific structure represented by the formula (A)below and/or a (partial) hydrolyzate thereof, or a mixture of thedisilane compound and/or a (partial) hydrolyzate thereof and afluorinated organo group-containing organosilicon compound representedby the formula (B) below and/or a (partial) hydrolyzate thereof, or aco-hydrolyzate of the mixture is used, there is obtained a coat havingimproved chemical resistance and mar resistance. The coat is effectiveas a protective coat on plastic and other substrates which lack suchproperties.

Since the coat resulting from the inventive composition has a lowrefractive index, the coat alone or in combination with a highrefractive index under-layer having an optical thickness offers a coathaving improved antireflection. The multilayer laminate is also improvedin transparency, and thus applicable as antireflective optical articlesor films having water repellency, anti-staining, anti-fingerprinting andmar resistance, for example, in displays such as computer displays, TVand plasma displays, polarizers in liquid crystal displays, transparentplastic lenses, covers in various instruments, and window panes inautomobiles and trains.

Therefore, the present invention provides a protective coat-formingcoating composition, a coated article having a protective coat formed bycuring the coating composition, and a multilayer laminate, all definedbelow.

In a first aspect, the invention provides a protective coat-formingcoating composition. One embodiment is a coating composition primarilycomprising a disilane compound having the formula (A):X_(m)R¹ _(3-m)Si—Y—SiR¹ _(3-m)X_(m)  (A)wherein R¹ is a monovalent hydrocarbon group of 1 to 6 carbon atoms, Yis a divalent organo group containing at least one fluorine atom, X is ahydrolyzable group, and m is 1, 2 or 3, or a (partial) hydrolyzatethereof.

In a preferred embodiment, the protective coat-forming coatingcomposition primarily comprises a mixture of (i) a disilane compoundhaving the formula (A) defined above or a (partial) hydrolyzate thereofand optionally, (ii) a fluorinated organo group-containing organosiliconcompound having the formula (B):Rf—SiX₃  (B)wherein Rf is a monovalent organo group containing at least one fluorineatom and X is a hydrolyzable group or a (partial) hydrolyzate thereof,wherein the content of component (i) is 60% by weight to 100% by weightof the mixture.

Another embodiment is a protective coat-forming coating compositionprimarily comprising a co-hydrolyzate of a mixture of

(i) a disilane compound having the formula (A):X_(m)R¹ _(3-m)Si—Y—SiR¹ _(3-m)X_(m)  (A)wherein R¹ is a monovalent hydrocarbon group of 1 to 6 carbon atoms, Yis a divalent organo group containing at least one fluorine atom, X is ahydrolyzable group, and m is 1, 2 or 3, or a (partial) hydrolyzatethereof and

(ii) a fluorinated organo group-containing organosilicon compound havingthe formula (B):Rf—SiX₃  (B)wherein Rf is a monovalent organo group containing at least one fluorineatom and X is a hydrolyzable group or a (partial) hydrolyzate thereof,wherein the content of component (i) is 60% by weight to less than 100%by weight of the mixture.

In all embodiments, the coating composition may further comprise 50 to99% by weight based on the coating composition of a solvent.

Most often, Y in formula (A) is

—CH₂CH₂(CF₂)_(n)CH₂CH₂—

wherein n is 2 to 20. In a preferred embodiment, the disilane compoundof formula (A) is

(R²O)₃Si—CH₂CH₂(CF₂)₄CH₂CH₂—Si(OR²)₃ or

(R²O)₃Si—CH₂CH₂(CF₂)₆CH₂CH₂—Si(OR²)₃

wherein R² is a monovalent hydrocarbon group of 1 to 6 carbon atoms.

Typically the coating composition cures into a coat having a refractiveindex of up to 1.410.

In a second aspect, the invention provides a coated article comprising atransparent substrate and a cured coat formed thereon from theprotective coat-forming coating composition of the first aspect, servingas a chemical resistant film; or a coated article comprising atransparent substrate and a cured coat formed thereon from theprotective coat-forming coating composition of the first aspect, servingas an antireflection film.

In a further embodiment, a coated article is provided comprising atransparent substrate; a layer formed thereon having a higher refractiveindex than the substrate; and a cured coat formed on the high refractiveindex layer from the protective coat-forming coating composition of thefirst aspect, serving as an antireflection film.

The coated article may further include a mar resistant protective layerbetween the substrate and the high refractive index layer.

In a preferred embodiment, the high refractive index layer comprises ametal oxide sol. Typically the metal oxide sol contains at least oneelement selected from among Ti, Sn, Ce, Al, Zr and In.

Preferably, a coating composition from which the high refractive indexlayer is formed is thermosetting or photo-curing. Also preferably, acoating composition from which the protective layer is formed isthermosetting or photo-curing.

Preferably, the transparent substrate comprises an organic resin and/oran inorganic material such as glass or ceramics, and more preferably, apolycarbonate resin, polyalkylene terephthalate resin, cellulosetriacetate resin, polystyrene resin or polyolefin resin.

Also contemplated herein is a multilayer laminate comprising the coatedarticle of the second aspect, a tackifier or adhesive layer lying on thetransparent substrate side of the coated article, and a release layerlying thereon. The transparent substrate is typically in the form offilm.

As used herein, the term “(partial) hydrolyzate” means that ahydrolyzate may be either a partially hydrolyzed product or a completelyhydrolyzed product.

As used herein, the phrase “composition primarily comprising acomponent” means that the composition comprises at least 50% by weight,especially at least 70% by weight of that component based on the totalweight of effective components excluding a solvent.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Component (i) in the protective coat-forming coating composition of theinvention is a disilane compound having the formula (A) or a (partial)hydrolyzate thereof.X_(m)R¹ _(3-m)Si—Y—SiR¹ _(3-m)X_(m)  (A)Herein R¹ is a monovalent hydrocarbon group of 1 to 6 carbon atoms, Y isa divalent organo group containing at least one fluorine atom, X is ahydrolyzable group, and m is equal to 1, 2 or 3.

More particularly, Y is a divalent organo group containing at least onefluorine atom, preferably 4 to 50 fluorine atoms, more preferably 8 to24 fluorine atoms. Illustrative, non-limiting examples of the divalentorgano group represented by Y are given below.

—C₂H₄—(CF₂)_(n)—C₂H₄—

—C₂H₄—CF(CF₃)—(CF₂)_(n)—CF(CF₃)—C₂H₄—

—C₂H₄—CF(C₂F₅)—(CF₂)_(n)—CF(C₂F₅)—C₂H₄—

—C₂H₄—CF(CF₃)CF₂—O(CF₂)_(n)O—CF₂CF(CF₃)—C₂H₄—

-   -   (Note that n is an integer of 2 to 20.)

—C₂H₄—C₆F₁₀—C₂H₄—

—C₂H₄—C₆F₄—C₂H₄—

In order for various functions such as antireflection, anti-staining andwater repellency to develop at a satisfactory level, inclusion of alarge amount of fluorine atoms is preferred. Since perfluoroalkylenegroups are rigid, inclusion of fluorine atoms as much as possible ispreferred for the purpose of obtaining a coat having a high hardness andmar resistance. Inclusion of a large amount of fluorine atoms leads tohigher chemical resistance. Therefore, Y is preferably a structure:

—CH₂CH₂(CF₂)_(n)CH₂CH₂— or

—C₂H₄—CF(CF₃)—(CF₂)_(n)—CF(CF₃)—C₂H₄—

wherein n is an integer of 2 to 20, and more preferably a structure:

—CH₂CH₂(CF₂)_(n)CH₂CH₂—

wherein n is an integer of 2 to 20.

The subscript n should have a value of 2 to 20, more preferably in therange of 4 to 12, most preferably in the range of 4 to 10. With a toolow value of n, various functions such as antireflection, anti-stainingand water repellency may not be fully developed, nor chemicalresistance. A too high value of n may lead to a reduced crosslinkeddensity, failing to provide satisfactory mar resistance.

R¹ is a monovalent hydrocarbon group of 1 to 6 carbon atoms.Illustrative are alkyl groups such as methyl, ethyl, propyl, butyl,hexyl and cyclohexyl and phenyl. Of these, methyl is preferred toprovide satisfactory mar resistance.

The subscript m is equal to 1, 2 or 3, preferably 2 or 3. To form a coathaving a high hardness, m=3 is recommended.

X is a hydrolyzable group. Illustrative examples include halogen atomssuch as Cl, and organoxy groups represented by OR² wherein R² is amonovalent C₁₋₆ hydrocarbon group, for example, alkoxy groups such asmethoxy, ethoxy, propoxy, isopropoxy and butoxy, alkenoxy groups such asisopropenoxy, acyloxy groups such as acetoxy, ketoxime groups such asmethyl ethyl ketoxime, and alkoxyalkoxy groups such as methoxyethoxy. Ofthese, alkoxy groups are preferred. Methoxy and ethoxy groups are mostpreferred because silane compounds having such groups are easy to handleand their reaction upon hydrolysis is easy to control.

Illustrative examples of the disilane compound satisfying the aboverequirement are given below.

(CH₃O)₃Si—C₂H₄—(CF₂)₄—C₂H₄—Si(OCH₃)₃

(CH₃O)₃Si—C₂H₄—(CF₂)₆—C₂H₄—Si(OCH₃)₃

(CH₃O)₃Si—C₂H₄—(CF₂)₈—C₂H₄—Si(OCH₃)₃

(CH₃O)₃Si—C₂H₄—(CF₂)₁₀—C₂H₄—Si(OCH₃)₃

(CH₃O)₃Si—C₂H₄—(CF₂)₁₆—C₂H₄—Si(OCH₃)₃

(C₂H₅O)₃Si—C₂H₄—(CF₂)₄—C₂H₄—Si(OC₂H₅)₃

(C₂H₅O)₃Si—C₂H₄—(CF₂)₆—C₂H₄—Si(OC₂H₅)₃

(CH₃O)₂(CH₃)Si—C₂H₄—(CF₂)₄—C₂H₄—Si(CH₃)(OCH₃)₂

(CH₃O)₂(CH₃)Si—C₂H₄—(CF₂)₆—C₂H₄—Si(CH₃)(OCH₃)₂

(CH₃O)(CH₃)₂Si—C₂H₄—(CF₂)₄—C₂H₄—Si(CH₃)₂(OCH₃)

(C₂H₅O)(CH₃)₂Si—C₂H₄—(CF₂)₆—C₂H₄—Si(CH₃)₂(OC₂H₅)

(CH₃O)₃Si—C₂H₄—CF(CF₃)—(CF₂)₄—CF(CF₃)—C₂H₄—Si(OCH₃)₃

(CH₃O)₃Si—C₂H₄—CF(CF₃)—(CF₂)₈—CF(CF₃)—C₂H₄—Si(OCH₃)₃

(CH₃O)₃Si—C₂H₄—CF(CF₃)—(CF₂)₁₂—CF(CF₃)—C₂H₄—Si(OCH₃)₃

Of these disilane compounds, the following compounds are preferred.

(CH₃O)₃Si—C₂H₄—(CF₂)₄—C₂H₄—Si(OCH₃)₃

(CH₃O)₃Si—C₂H₄—(CF₂)₆—C₂H₄—Si(OCH₃)₃

(CH₃O)₃Si—C₂H₄—(CF₂)₈—C₂H₄—Si(OCH₃)₃

(C₂H₅O)₃Si—C₂H₄—(CF₂)₄—C₂H₄—Si(OC₂H₅)₃

(C₂H₅O)₃Si—C₂H₄—(CF₂)₆—C₂H₄—Si(OC₂H₅)₃

Component (ii) which can be used in combination with the disilanecompound of formula (A) is a fluorinated organo group-containingorganosilicon compound having the formula (B) or a (partial) hydrolyzatethereof.Rf—SiX₃  (B)Herein Rf is a monovalent organo group containing at least one fluorineatom and X is a hydrolyzable group.

More particularly, Rf is a monovalent organo group containing at leastone fluorine atom, preferably 3 to 25 fluorine atoms, more preferably 3to 17 fluorine atoms. Illustrative examples are given below.

CF₃C₂H₄—

CF₃(CF₂)₃C₂H₄—

CF₃(CF₂)₅C₂H₄—

CF₃(CF₂)₇C₂H₄—

CF₃(CF₂)₉C₂H₄—

CF₃(CF₂)₁₁C₂H₄—

CF₃(CF₂)₇CONHC₃H₆—

CF₃(CF₂)₇CONHC₂H₄NHC₃H₆—

CF₃(CF₂)₇C₂H₄OCOC₂H₄C₃H₆—

CF₃(CF₂)₇C₂H₄OCONHC₃H₆—

CF₃(CF₂)₇SO₂NHC₃H₆—

C₃F₇O(CF(CF₃)CF₂O)_(p)CF(CF₃)CONHC₃H₆—

Herein, p is at least 1, especially 1 to 3.

Of these, the following groups are preferred because they are free of apolar moiety.

CF₃C₂H₄—

CF₃(CF₂)₃C₂H₄—

CF₃(CF₂)₇C₂H₄—

X is a hydrolyzable group as exemplified for component (i).

Illustrative examples of the fluorinated organo group-containingorganosilicon compound satisfying the above requirement are given below.

CF₃C₂H₄—Si(OCH₃)₃

CF₃C₂H₄—Si(OC₂H₅)₃

CF₃(CF₂)₃C₂H₄—Si(OCH₃)₃

CF₃(CF₂)₃C₂H₄—Si(OC₂H₅)₃

CF₃(CF₂)₅C₂H₄—Si(OCH₃)₃

CF₃(CF₂)₇C₂H₄—Si(OCH₃)₃

CF₃(CF₂)₇C₂H₄—Si(OC₂H₅)₃

CF₃(CF₂)₉C₂H₄—Si(OCH₃)₃

CF₃(CF₂)₁₁C₂H₄—Si(OCH₃)₃

CF₃(CF₂)₇CONHC₃H₆—Si(OCH₃)₃

CF₃(CF₂)₇CONHC₂H₄NHC₃H₆—Si(OCH₃)₃

CF₃(CF₂)₇C₂H₄OCOC₂H₄SC₃H₆—Si(OCH₃)₃

CF₃(CF₂)₇C₂H₄OCONHC₃H₆—Si(OCH₃)₃

CF₃(CF₂)₇SO₂NHC₃H₆—Si(OCH₃)₃

C₃F₇O(CF(CF₃)CF₂O)_(p)CF(CF₃)CONHC₃H₆—Si(OCH₃)₃

Herein, p is at least 1.

Of these, the following compounds are preferred.

CF₃C₂H₄—Si(OCH₃)₃

CF₃(CF₂)₃C₂H₄—Si(OCH₃)₃

CF₃(CF₂)₇C₂H₄—Si(OCH₃)₃

In the invention, component (i) may be used alone or in combination withcomponent (ii). In the second embodiment wherein component (i) is usedin combination with component (ii), the content of component (i) shouldbe from 60% by weight to less than 100% by weight. A component (i)content of less than 60% by weight is not preferred because acrosslinked density becomes too low to provide satisfactory marresistance and so, the function of a protective coat becomesinsufficient. The content of component (i) should preferably be at least95% by weight. In consideration of the addition effect of component(ii), the content of component (i) should preferably be up to 99.5% byweight.

In a further embodiment of the invention, a co-hydrolyzate of a mixtureof components (i) and (ii) is used.

While the coating composition of the invention primarily comprisescomponent (i) alone, or a mixture of components (i) and (ii) or aco-hydrolyzate of the mixture, an organosilicon compound or a (partial)hydrolyzate thereof may be incorporated as long as the desiredproperties are not compromised.

Examples of the organosilicon compound which can be used in combinationwith components (i) and (ii) include silicates such astetraethoxysilane, alkylsilanes such as methyltrimethoxysilane,hexyltrimethoxysilane and decyltrimethoxysilane, phenylsilanes such asphenyltrimethoxysilane, and silane coupling agents such asγ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane,γ-methacryloxypropyltrimethoxysilane, andγ-mercaptopropyltrimethoxysilane. In particular, tetraalkoxysilane iseffective on combined use for the purpose of improving mar resistancebecause they serve to increase a crosslinked density, but tend to renderthe coats hydrophilic and can detract from such functions asanti-staining and water repellency and chemical resistance. It is thusrecommended to avoid the use of large amounts of tetraalkoxysilane. Thetetraalkoxysilane is preferably used in an amount of up to 5 parts, morepreferably up to 2 parts, even more preferably up to 1 parts by weightper 100 parts by weight of component (i) or components (i) and (ii)combined.

The organosilicon compound which can be used in combination with thecompounds of formulae (A) and (B), i.e., components (i) and (ii) may beused as such or in a (partially) hydrolyzed form or in a form hydrolyzedin the following solvent. From the standpoint of accelerating the curespeed after coating, it is recommended to use the organosilicon compoundin a (partially) hydrolyzed form. The amount of water used in hydrolysisis preferably such that the molar ratio of H₂O/Si—X is between 0.1 and10.

Hydrolysis may be carried out by a method known to the art. Illustrativeexamples of hydrolytic catalysts or hydrolytic condensation curingcatalysts include acids such as hydrochloric acid, acetic acid andmaleic acid; bases such as sodium hydroxide (NaOH), ammonia, aminecompounds (e.g., triethylamine, dibutylamine, hexylamine, octylamine,dibutylamine) and salts of amine compounds, and quaternary ammoniumsalts (e.g., benzyltriethylammonium chloride, tetramethylammoniumhydroxide); fluorides such as potassium fluoride and sodium fluoride;solid acidic catalysts and solid basic catalysts (e.g., ion-exchangeresin catalysts); the metal salts of organic carboxylic acids, such asiron 2-ethylhexoate, titanium naphthenate, zinc stearate and dibutyltindiacetate; organometallic compounds such as tetrabutoxytitanium,tetra-1-propoxytitanium, organotitanium esters (e.g.,dibutoxy(bis-2,4-pentanedionate)titanium,di-1-propoxy(bis-2,4-pentanedionate)titanium), tetrabutoxyzirconium,tetra-1-propoxyzirconium, organozirconium esters (e.g.,dibutoxy(bis-2,4-pentane-dionato)zirconium,di-1-propoxy(bis-2,4-pentanedionato)-zirconium), alkoxyaluminumcompounds (e.g., aluminum triisopropoxide) and aluminum chelatecompounds (e.g., aluminum acetylacetonate complex); andaminoalkyl-substituted alkoxysilanes such asγ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane,N-(β-aminoethyl)-γ-aminopropyl-trimethoxysilane andN-(β-aminoethyl)-γ-aminopropyltriethoxy-silane. Any one or mixturesthereof may be used as the catalyst.

The catalyst is preferably used in an amount of 0.01 to 10 parts byweight, and more preferably 0.1 to 1 part by weight, per 100 parts byweight of the organosilicon compound to be hydrolyzed. At less than 0.01part by weight, the reaction generally takes too much time to reachcompletion, or may even fail to proceed altogether. On the other hand,the use of more than 10 parts by weight of catalyst not only entailsexcessive cost, but also may increase the number of side reactions andresult in discoloration of the resulting composition or cured coat.

To adjust the desired properties of the coat such as hardness, marresistance and electrical conductivity, the coating composition mayfurther include fine particles of an inorganic oxide such as silica,aluminum oxide, titanium oxide, zinc oxide, zirconium oxide, ceriumoxide, tin oxide, indium oxide or a complex oxide thereof, or hollowsols thereof. Of these, colloidal silica and hollow silica sol arepreferred when it is desired to maintain the coat at a low refractiveindex. Suitable fine inorganic oxide particles have an average primaryparticle size of preferably 0.001 to 0.1 μm, and more preferably 0.001to 0.05 μm. At an average primary particle size larger than 0.1 μm, thecured coat that is formed of the particle-filled composition tends todecline its transparency. If desired, these fine inorganic oxideparticles may be surface-treated with an organometallic compound such asa silane, titanium, aluminum or zirconium coupling agent.

Fine inorganic oxide particles, when included in the composition, areadded in an amount of preferably 0 to 30 parts by weight, and morepreferably 0.1 to 10 parts by weight, calculated as solids, per 100parts by weight of component (i) or components (i) and (ii) combined.When the composition contains more than 30 parts by weight of fineinorganic oxide particles, the cured coat that is formed therefrom tendsto decline its transparency.

The fine inorganic oxide particles are generally used in the form of adispersion within a dispersing medium, which is typically water or anorganic solvent. When water is used as the dispersing medium for theinorganic oxide particles, the dispersing medium is set within a pHrange of preferably 2 to 10, and more preferably 3 to 7. Organicsolvents which are suitable as the dispersing medium for the fineinorganic oxide particles include alcohols such as methanol, isopropylalcohol, ethylene glycol, butanol and ethylene glycol monopropyl ether;ketones such as methyl ethyl ketone and methyl isobutyl ketone; aromatichydrocarbons such as toluene and xylene; amides such asdimethylformamide, dimethylacetamide and N-methylpyrrolidone; esterssuch as ethyl acetate, butyl acetate and γ-butyrolactone; ethers such astetrahydrofuran and 1,4-dioxane; and β-diketones and β-ketoesters suchas acetylacetone and ethyl acetoacetate. Of these, alcohols and ketonesare preferred. The above organic solvents may be used alone or asmixtures of two or more thereof as the dispersing medium.

The coating composition may be used after dilution with a solvent.Suitable solvents for this purpose include alcohols such as methanol,ethanol, propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutylalcohol, sec-butyl alcohol, t-butyl alcohol and diacetone alcohol;glycol ethers such as ethylene glycol monomethyl ether, ethylene glycolmonoethyl ether, propylene glycol monomethyl ether and propylene glycolmonoethyl ether; ketones such as acetone, methyl ethyl ketone, methylisobutyl ketone and acetylacetone; esters such as ethyl acetate, butylacetate and ethyl acetoacetate; xylene and toluene. The solvent may beadded in any desired amount to form a coating liquid. For ease ofapplication, ease of control of coating thickness and the stability ofthe coating liquid, the content of the solvent in the coating liquid ispreferably 50 to 99% by weight, more preferably 70 to 98% by weight.

The coating composition of the invention may further include optionalcomponents, for example, organic or inorganic UV absorbers, levelingagents, and buffer agents for controlling the system to a level of pH 2to 7 at which silanol groups remain stable, such as acetic acid-sodiumacetate or disodium hydrogen phosphate-citric acid.

On use, the coating composition is applied to various substrates andcured to form a cured coat. In the curing step, a curing catalystsimilar to the aforementioned hydrolytic catalyst or hydrolyticcondensation curing catalyst may be used in a catalytic amount wherebycuring is performed in a conventional way.

The cured coat formed on the substrate surface from the inventivecoating composition generally has a thickness of 0.01 to 10.0 μm,preferably 0.05 to 8.0 μm. To impart a desired function such asantireflection, the coat is adjusted to an optical film thickness ofabout 0.1 μm sufficient to attain the purpose. When the coatingcomposition is applied to the substrate surface, any desired applicationtechnique may be used, for example, dipping, spin coating, flow coating,roll coating, spray coating and screen printing. For ease of control offilm thickness, dipping, spray coating and roll coating techniques arepreferably used to apply the composition to a desired film thickness.After the coating composition is applied to various substrates in thisway, the coating may be cured by heating or exposure to ultravioletradiation, obtained a cured coat.

When the protective coat formed from the inventive coating compositionis used for the antireflection purpose, the cured coat preferably has arefractive index of up to 1.410. The cured coat having a refractiveindex of up to 1.410 is applicable alone as an anti-glare layer. Arefractive index of up to 1.400 is more preferred.

The transparent substrate to which is applied the inventive coatingcomposition is typically made of glass, ceramics or plastics. Anyplastic having excellent optical characteristics may be used for thispurpose. Illustrative, non-limiting examples include polycarbonateresins, polyalkylene terephthalate resins such as PET, cellulose resinssuch as cellulose diacetate, cellulose acetate butyrate and cellulosetriacetate, acrylic resins, polystyrene resins, polyimide resins,polyester resins, polyethersulfone resins, liquid crystal resins such aspolyarylates, polyurethane resins, polysulfone resins, polyetherketoneresins, polyolefin resins such as trimethylpentene and polyvinylnorbornene, and hybrid resins thereof. Of these, polycarbonate resins,polyalkylene terephthalate resins such as PET, cellulose triacetateresins, polystyrene resins and polyolefin resins are especiallypreferred. The transparent substrate may be in the form of a moldedpart, sheet, plate or film. A film form transparent substrate isespecially preferred for ease of coating operation.

On the cured coat formed on the substrate surface from the inventivecoating composition, any of oil repellent, anti-staining coatings may beoverlaid. Namely an oil repellent, anti-staining coating may be providedon the antireflective article (having the cured coat formed on thesubstrate), for the purpose of preventing the antireflective articlefrom oily staining like fingerprinting or facilitating removal of suchoily stains.

When the transparent substrate having the inventive coating compositionapplied and cured thereto is used as an antireflective member possessingboth excellent mar resistance and chemical resistance, the coatedsubstrate may be attached to another transparent substrate prior to use.For use of the coated substrate after attachment to another transparentsubstrate, any well-known adhesive selected from acrylic, epoxy,polyimide and silicone base adhesives and pressure-sensitive adhesivesmay be applied to the back surface of the substrate remote from thesurface coated with the inventive coating composition. Acrylic andsilicone base adhesives are preferred. The adhesive layer may have athickness of about 1 to 500 μm. Too thin an adhesive layer fails toprovide an appropriate bonding force whereas too thick a layer isuneconomical. A protective plastic sheet may be provided thereon for thepurpose of surface protection.

In an embodiment wherein a coated article comprising a transparentsubstrate and a cured coat formed thereon from the inventive coatingcomposition is used as an antireflective member, a layer having a higherrefractive index than the transparent substrate may be formed andinterleaved between the substrate and the cured coat for enhancingantireflective property. In a further embodiment, a mar resistantprotective layer may be formed and interleaved between the substrate andthe high refractive index layer.

In these embodiments, the curable resin of which the high refractiveindex layer (or high refractive index cured layer) is formed may beselected from among well-known thermoplastic resins, moisture-curable,thermosetting and photo-curable organic resins and silicone resins.Exemplary of moisture-curable, thermosetting and photo-curable organicresins are thermosetting acrylic resins, moisture-curable acrylicresins, thermoplastic acrylic resins, UV/EB-curable acrylic resins,silane or siloxane-modified acrylic resins, urethane resins,UV/EB-curable epoxy resins, thermosetting silicone resins,moisture-curable silicone resins, UV/EB-curable silicone resins, and thelike. Of these, thermosetting and photo-curable resins are preferred.Especially, silicone resins obtained through hydrolysis of varioushydrolyzable silane compounds and optional (partial) hydrolyticcondensation are advantageous because coatings thereof have a highhardness and are highly adherent to the protective coating layer.UV-curable acrylic resins, epoxy resins and silicone resins are alsoadvantageous because of good adhesion of coatings thereof and highproductivity.

For systems to be polymerized and cured by exposure to radiation such asultraviolet light or electron beams, it is preferred to add aphotopolymerization initiator and carry out photopolymerization.Illustrative examples of photopolymerization initiators includearylketone photopolymerization initiators (e.g., acetophenones,benzophenones, alkylaminobenzophenones, benzils, benzoins, benzoinethers, benzil dimethyl ketals, benzoylbenzoates and α-acyloximeesters), sulfur-containing photopolymerization initiators (e.g.,sulfides, thioxanthones), acylphosphine oxide photopolymerizationinitiators, as well as other photopolymerization initiators.

The photopolymerization initiator may be used in combination with aphotosensitizer such as an amine. Specific examples of suitablephotopolymerization initiators include 4-phenoxydichloroacetophenone,4-t-butyldichloroacetophenone, 4-t-butyltrichloroacetophenone,diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one,1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one,1-(4-dodecylphenyl)-2-methylpropan-1-one,1-{4-(2-hydroxyethoxy)phenyl}-2-hydroxy-2-methylpropan-1-one,1-hydroxycyclohexyl phenyl ketone,2-methyl-1-{4-(methylthio)phenyl}-2-morpholinopropan-1-one, benzil,benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropylether, benzoin isobutyl ether, benzil dimethyl ketal, benzophenone,benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone,hydroxybenzophenone, benzophenone acrylate,3,3′-dimethyl-4-methoxybenzophenone,3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone,9,10-phenanthrenequinone, camphorquinone, dibenzosuberone,2-ethylanthraquinone, 4′,4″-diethylisophthalophenone, α-acyloxime ester,methyl phenylglyoxylate, 4-benzoyl-4′-methyldiphenylsulfide,thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone,2,4-dimethylthioxanthone, isopropylthioxanthone,2,4-dichlorothioxanthone, 2,4-diethylthioxanthone,2,4-diisopropylthioxanthone, 2,4,6-trimethylbenzoyldiphenylphosphineoxide, benzoyl diphenylphosphine oxide, 2,6-dimethylbenzoyldiphenylphosphine oxide andbis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide.

The high refractive index cured layer must have a high hardness and ashigh a refractive index as possible. It is preferred for the highrefractive index layer to contain a metal oxide sol and to have arefractive index of at least 1.60. The metal oxide sol included forincreasing the refractive index is preferably ultra-fine particleshaving a refractive index of at least 1.60. This high refractive indexmetal oxide sol has an average particle size of preferably 1 to 100 nm,and more preferably 1 to 50 nm. No particular limitation is imposed onthe amount of high refractive index metal oxide sol included, althoughthe metal oxide sol is preferably used in an amount of 5 to 500 parts byweight, and especially 70 to 250 parts by weight, per 100 parts byweight of the curable resin in the high refractive index layer-formingcomposition. More than 500 parts by weight of metal oxide sol tends togive rise to undesirable effects such as haze in the cured coating,whereas the use of less than 5 parts by weight may fail to increase therefractive index.

A high refractive index metal oxide sol with a refractive index which ishigher than that of the (unfilled) cured resin and is at least 1.60 isdesirable for increasing the refractive index of the high refractiveindex cured resin layer. Specific examples of preferred high refractiveindex metal oxide sols include metal oxides such as ZnO (n=1.90), TiO₂(n=2.3 to 2.7), Sb₂O₅ (n=1.71), Y₂O₃ (n=1.87), La₂O₃ (n=1.95), ZrO₂(n=2.05), Al₂O₃ (n=1.63) and the complex oxide of indium and tin knownas ITO (n=1.95), as well as complex oxides including any of the above.Other metal oxide sols such as In₂O₃, SnO₂, CeO₂ and Fe₂O₃ may also beused. The use of a titanium atom-containing metal oxide sol isespecially preferred since it provides a higher refractive index. Thehigh refractive index metal oxide sol may be surface-modified with asilane compound, an organic functional group-containing silane couplingagent or titanium coupling agent, or an organic functionalgroup-containing acrylic polymer in order to enhance the dispersionstability.

Examples of the dispersing medium in which the high refractive indexmetal oxide sol is dispersed include water, alcohols such as methanoland ethanol, esters such as ethyl acetate and butyl acetate, ethers suchas propylene glycol monoethyl ether, and ketones such as methyl ethylketone and methyl isobutyl ketone.

The resin composition for forming the high refractive index cured layermay be diluted with a solvent prior to use. Suitable solvents includemethanol, ethanol, diacetone alcohol, propylene glycol monomethyl ether,ethylene glycol monomethyl ether, propylene glycol monoethyl ether,ethylene glycol monoethyl ether, isobutyl alcohol, isopropyl alcohol,n-butyl alcohol, n-propyl alcohol, acetone, methyl ethyl ketone, methylisobutyl ketone, acetylacetone, ethyl acetoacetate, ethyl acetate, butylacetate, xylene, and toluene.

If necessary, well-known additives such as leveling agents that are usedin prior-art coating compositions may also be included.

To maintain the desired optical characteristics (e.g., antireflectiveproperties), the cured film formed from the above-formulated compositionas the high refractive index layer should be a thin film having athickness complying with the desired refractive index. The preferredfilm thickness is in the range of 0.02 to 3 μm, and especially 0.05 to0.5 μm.

Described below is the protective layer which may be disposed betweenthe transparent substrate and the high refractive index layer forproviding satisfactory mar resistance.

The protective layer must have an excellent adhesion to various types oftransparent substrates (e.g., polycarbonate resin, polyalkyleneterephthalate resins such as polyethylene terephthalate, celluloseresins such as cellulose triacetate, and glass) and an appropriatehardness at a certain minimum thickness. The protective layer may bemade of thermoplastic acrylic resins, UV/EB-curable acrylic resins orsilicone resins having functional organic groups such as epoxy groups.Of these, thermosetting or photo-curable resins are preferred, withacrylic resins being most preferred for ease of working. Specificexamples of the protective layer include:

(A) a layer prepared by subjecting a radiation-polymerizablecomposition, and in particular a composition comprising a (meth)acrylicfunctional group-bearing organosilicon compound, to radiationpolymerization so as to effect curing;

(B) a layer prepared by curing a composition comprising an acrylicpolymer, and especially a composition comprising a hydrolyzable silylgroup-bearing acrylic polymer; and

(C) a layer composed of an acrylic polymer, and in particular athermoplastic acrylic resin containing methyl methacrylate as a majorcomonomer and having an excellent heat resistance and a high hardness.

To adjust the desired properties of a coating, such as hardness, marresistance and electrical conductivity, it is desirable to include alsofine particles of an inorganic oxide such as silica, aluminum oxide,titanium oxide, zinc oxide, zirconium oxide, cerium oxide, tin oxide,indium oxide, or a complex oxide thereof. Colloidal silica is especiallydesirable for this purpose. If desired, the fine inorganic oxideparticles may be surface-treated with an organometallic compound such asa silane, titanium, aluminum or zirconium coupling agent.

Fine particulate inorganic oxide, if used, is added in an amount ofpreferably 0.1 to 80 parts by weight, and most preferably 1 to 50 partsby weight, calculated as solids, per 100 parts by weight of the resin.At more than 80 parts by weight, a cured coating obtained from thefilled composition tends to decline its transparency.

A conventional ultraviolet absorber may be added to the protective layerto inhibit photo-degradation of the substrate. UV absorbers includeinorganic UV absorbers such as fine particulate titanium oxide and zincoxide, and organic UV absorbers. Preferred organic UV absorbers includederivatives of compounds having a hydroxybenzophenone, benzotriazole,cyanoacrylate or triazine skeleton. Polymers such as vinyl polymerscontaining these UV absorbers on side chains are also preferred.Specific examples include 2,4′-dihydroxybenzophenone,2,2′,4,4′-tetrahydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone,2-hydroxy-4-methoxybenzophenon-5-sulfonic acid,2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone,2-hydroxy-4-n-benzyloxybenzophenone,2,2′-dihydroxy-4,4′-dimethoxybenzopheone,2,2′-dihydroxy-4,4′-diethoxybenzophenone,2,2′-dihydroxy-4,4′-dipropoxybenzophenone,2,2′-dihydroxy-4,4′-dibutoxybenzophenone,2,2′-dihydroxy-4-methoxy-4′-propoxybenzophenone,2,2′-dihydroxy-4-methoxy-4′-butoxybenzophenone,2,3,4-trihydroxybenzophenone,2-(2-hydroxy-5-t-methylphenyl)benzotriazole,2-(2-hydroxy-5-t-octylphenyl)benzotriazole,2-(2-hydroxy-3,5-di-t-butylphenyl)benzotriazole,ethyl-2-cyano-3,3-diphenyl acrylate, 2-ethylhexyl-2-cyano-3,3-diphenylacrylate, 2-(2-hydroxy-4-hexyloxyphenyl)-4,6-diphenyltriazine,4-(2-acryloxyethoxy)-2-hydroxybenzophenone polymers and2-(2′-hydroxy-5′-methacryloxyethylphenyl)-2H-benzotriazole polymers.These organic UV absorbers may be used singly or in combinations of twoor more thereof.

The thickness of the protective layer is not particularly limited aslong as satisfactory mar resistance is obtainable. Usually the thicknessis in a range of 0.1 to 10 μm. Too thin a layer fails to providesatisfactory mar resistance whereas too thick a layer is likely tocrack. The preferred thickness is in a range of 0.2 to 5 μm.

The protective coat obtained from the inventive coating composition,which has a low refractive index, may also serve as an antireflectivecoat when used alone or when an underlying layer having a highrefractive index is formed to an optical film thickness. The multilayerlaminate comprising at least the protective coat and the high refractiveindex layer is fully transparent and thus suitable for use asantireflective optical members or films endowed with excellent waterrepellence, stain-proofing properties, ability to preventfingerprinting, and mar resistance. Examples of such applicationsinclude various types of displays (e.g., computer displays, televisions,plasma displays), polarizers for liquid-crystal displays, transparentplastic lens, covers for various types of instruments, and window glassfor automobiles and trains.

EXAMPLE

Synthesis examples, examples of the invention, and comparative examplesare given below by way of illustration, but are not intended to limitthe scope of the invention. In the examples, all parts and percents areby weight. Average molecular weight values are number average molecularweights determined by gel permeation chromatography (GPC) usingpolystyrene standards.

Synthesis Example 1

A 1-liter flask equipped with a stirrer, a condenser and a thermometerwas charged with 29.9 g (0.05 mole) of a disilane compound (I) shownbelow and 125 g of t-butanol. With stirring at 25° C., 10 g of 0.1Naqueous acetic acid was added dropwise over 10 minutes. Stirring wascontinued at 25° C. for 20 hours, bringing hydrolysis to completion. Tothe reaction mixture were added 2 g of aluminum acetylacetonate as acondensation catalyst and 1 g of polyether-modified silicone as aleveling agent. The mixture was stirred for another 30 minutes, yieldinga protective coat-forming coating composition solution A.(CH₃O)₃Si—C₂H₄—C₆F₁₂—C₂H₄—Si(OCH₃)₃  (I)

To the solution were added 670 g of ethanol, 40 g of propylene glycolmonomethyl ether, and 40 g of diacetone alcohol. This dilution yielded aprotective coat-forming coating composition solution A-d.

Synthesis Example 2

A 2-liter flask equipped with a stirrer, a condenser and a thermometerwas charged with 29.1 g (0.05 mole) of a disilane compound (II) shownbelow and 125 g of ethanol. With stirring at 25° C., 1 g of a cationexchange resin (Purolite International Ltd.) was added, and 10 g ofwater was added dropwise over 10 minutes. Stirring was continued at 25°C. for 20 hours, bringing hydrolysis to completion. The ion exchangeresin was filtered off, after which 2 g of aluminum acetylacetonate as acondensation catalyst and 1 g of polyether-modified silicone as aleveling agent were added to the reaction mixture. The mixture wasstirred for another 30 minutes, yielding a protective coat-formingcoating composition solution B.(C₂H₅O)₃Si—C₂H₄—C₄F₈—C₂H₄—Si(OC₂H₅)₃  (II)

To the solution were added 650 g of ethanol, 50 g of propylene glycolmonomethyl ether, and 50 g of diacetone alcohol. This dilution yielded aprotective coat-forming coating composition solution B-d.

Synthesis Example 3

The procedure of Synthesis Example 1 was repeated except that 39.9 g(0.05 mole) of a disilane compound (III) shown below was used instead ofthe disilane compound (I). By following the subsequent procedure tosolution A-d, a protective coat-forming coating composition solution C-dwas obtained.(CH₃O)₃Si—C₂H₄—C₁₀F₂₀—C₂H₄—Si(OCH₃)₃  (III)

Synthesis Example 4

The procedure of Synthesis Example 1 was repeated except that a mixtureof 23.9 g (0.04 mole) of the disilane compound (I) and 2.2 g (0.01 mole)of a silane compound (IV): CF₃CH₂CH₂—Si(OCH₃)₃ was used instead of thedisilane compound (I). By following the subsequent procedure to solutionA-d, a protective coat-forming coating composition solution D-d wasobtained.

Synthesis Example 5

The procedure of Synthesis Example 1 was repeated except that a mixtureof 28.7 g (0.048 mole) of the disilane compound (I) and 1.1 g (0.002mole) of a silane compound (V): C₈F₁₇CH₂CH₂—Si(OCH₃)₃ was used insteadof the disilane compound (I). By following the subsequent procedure tosolution A-d, a protective coat-forming coating composition solution E-dwas prepared.

Synthesis Example 6 (Comparison)

A 3-liter flask equipped with a stirrer, a condenser and a thermometerwas charged with 9.0 g (0.015 mole) of the disilane compound (I), 11.4 g(0.02 mole) of the fluorinated silane (V), 2.3 g (0.015 mole) ofSi(OCH₃)₄, and 570 g of t-butanol. With stirring at 25° C., 3.7 g of 1%aqueous hydrochloric acid was added. Stirring was continued at 25° C.for 24 hours, yielding a protective coat-forming coating compositionsolution F.

Synthesis Example 7 (Comparison)

A 3-liter flask equipped with a stirrer, a condenser and a thermometerwas charged with 22.5 g (0.025 mole) of a disilane compound (VI) shownbelow, 5.9 g (0.025 mole) of γ-glycidoxypropyltrimethoxysilane, and 520g of diacetone alcohol. With stirring below 10° C., 3.4 g of 1% aqueousacetic acid was added over 10 minutes. Stirring was continued for onehour below 10° C. and 5 days at 25° C. Thereafter, 1.1 g of aluminumacetylacetonate as a condensation catalyst was added, yielding aprotective coat-forming coating composition solution G.(CH₃O)₃Si—C₂H₄CF(CF₃)C₈F₁₆CF(CF₃)C₂H₄—Si(OCH₃)₃  (VI)

Synthesis Example 8 (Comparison)

A 0.1-liter flask equipped with a stirrer, a condenser and a thermometerwas charged with 2.84 g (0.005 mole) of the fluorinated silane (V), 7.2g (0.033 mole) of the fluorinated silane (IV), 2.6 g (0.013 mole) ofSi(OC₂H₅)₄, and 5 g of isobutanol. With stirring at room temperature, 3g of 0.2N aqueous acetic acid was added over 5 minutes. Further, 0.1 gof acetylacetonate was added. Stirring was continued at room temperaturefor 8 hours, bringing hydrolytic condensation to completion.

To 10 g of the solution were added 15 g of diacetone alcohol, 150 g ofethanol, and 0.1 g of polyether-modified silicone. A protectivecoat-forming coating composition solution H was prepared.

Synthesis Example 9 (Comparison)

The procedure of Synthesis Example 1 was repeated except that a mixtureof 12.0 g (0.02 mole) of the disilane compound (I) and 17.0 g (0.03mole) of the fluorinated silane (V) was used instead of the disilanecompound (I). By following the subsequent procedure to solution A-d, aprotective coat-forming coating composition solution J was prepared.

Synthesis Example 10

A 2-liter flask equipped with a stirrer, a condenser and a thermometerwas charged with 236.3 g (1.00 mole) ofγ-glycidoxypropyltrimethoxysilane, 74.5 g (0.30 mole) ofγ-glycidoxypropyldiethoxysilane and 700 g of a methanol-dispersed solhaving 30% of active ingredients TiO₂/ZrO₂/SiO₂ in a weight ratio of85/3/12, with a primary particle size of 20 nm. While stirring at roomtemperature, 70 g of 0.1N aqueous acetic acid was added dropwise overone hour. Stirring was continued at room temperature for another fivehours, bringing hydrolysis to completion. To the reaction mixture wereadded 150 g of diacetone alcohol, 2 g of aluminum acetylacetonate as acondensation catalyst and 2 g of polyether-modified silicone as aleveling agent. Stirring was continued for another 30 minutes, yieldinga silicone solution containing a high refractive index sol. Ethanol (600g) was added to 100 g of the solution, thereby giving a heat-curable,high refractive index layer-forming coating composition K.

Synthesis Example 11

A 1-liter flask equipped with a stirrer, a condenser and a thermometerwas charged with 82.0 g (0.35 mole) of γ-acryloxypropyltrimethoxysilane,32.7 g (0.15 mole) of γ-acryloxypropylmethyldimethoxysilane, 104.2 g(0.50 mole) tetraethoxysilane and 50 g of isobutanol. With stirring at10° C., 65 g of 0.1N aqueous acetic acid was added dropwise over onehour. Stirring was continued at room temperature for 5 hours, bringinghydrolysis to completion. To the reaction mixture were added 150 g ofdiacetone alcohol, 1 g of aluminum acetylacetonate as a condensationcatalyst and 1 g of polyether-modified silicone as a leveling agent.Stirring was continued for another 30 minutes, yielding an acrylicfunctional group-bearing silicone solution L.

To 100 g of silicone solution L were added 50 g of trimethylolpropanetriacrylate as a polyfunctional acrylic component, 50 g of propyleneglycol monomethyl ether, and 1 g of2-hydroxy-2-methyl-1-phenylpropan-1-one as a photo-polymerizationinitiator. Stirring yielded a UV-curable, protective layer-formingcoating composition solution M.

Synthesis Example 12

To 100 g of acrylic functional group-bearing silicone solution L wereadded 80 g of a methanol-dispersed sol containing 30% of activeingredients TiO₂/ZrO₂/SiO₂ in a weight ratio of 85/3/12 with a primaryparticle size of 20 nm, 10 g of trimethylolpropane triacrylate, 1 g ofaluminum acetylacetonate as a condensation catalyst, 1 g ofpolyether-modified silicone as a leveling agent, and 1 g of2-hydroxy-2-methyl-1-phenylpropan-1-one as a photo-polymerizationinitiator. The mixture was stirred at room temperature.

To 100 g of the silicone solution was added 500 g of ethanol. Thisdilution yielded a UV-curable, high refractive index layer-formingcoating composition N.

Synthesis Example 13

A 1-liter flask equipped with a stirrer, a condenser and a thermometerwas charged with 24.8 g (0.10 mole) ofγ-methacryloxypropyltrimethoxysilane and 450 g of isopropanol, followingwhich 300 g of colloidal silica dispersed in water (active ingredientcontent, 20%) was added dropwise. Next, 0.1 g of tetramethylammoniumhydroxide was added and the mixture was stirred for 3 hours underheating at 50° C., yielding a silica sol that was surface-treated withmethacrylic functional silane.

To 100 g of the surface-treated silica sol were added 40 g of acrylicfunctional group-bearing silicone solution L, 40 g of trimethylolpropanetriacrylate, 20 g of hexamethylenediol diacrylate, and 1 g of2-hydroxy-2-methyl-1-phenylpropan-1-one. Stirring gave a UV-curable,protective layer-forming coating composition solution P.

Synthesis Example 14

A 1-liter flask equipped with a stirrer, a condenser and a thermometerwas charged with 330 g of a 2:1 mixture of the solvents diacetonealcohol and methyl isobutyl ketone, which was heated to 80° C. While thesolvent mixture was heated and stirred under a nitrogen atmosphere, amixture of 24.8 g (0.10 mole) of γ-methacryloxypropyltrimethoxysilane,180 g (1.80 moles) of methyl methacrylate, 14.2 g (0.10 mole) ofglycidyl methacrylate and 2 g of azobisisobutyronitrile was addeddropwise over 30 minutes. Heating and stirring at 80° C. were continuedfor a further 5 hours, giving a solution of hydrolyzable silylgroup-bearing acrylic polymer having a number-average molecular weightof 125,000.

Separately, 60 g of 0.1N aqueous acetic acid was added dropwise over 30minutes to a mixture of 136 g (1.00 mole) of methyltrimethoxysilane and72 g of isopropanol at room temperature. Following the completion ofdropwise addition, 200 g of the acrylic polymer solution prepared above,0.1 g of sodium formate as a condensation catalyst, 10 g of acetic acid,and 1 g of polyether-modified silicone as a leveling agent were added tothe resulting solution. The mixture was stirred, yielding athermosetting, protective layer-forming coating composition solution Qhaving an active ingredient content of 31%.

Synthesis Example 15

As in Synthesis Example 14, a mixture of 24.8 g (0.20 mole) ofγ-methacryloxypropyltrimethoxysilane, 160 g (1.60 moles) of methylmethacrylate, 64.6 g (0.20 mole) of2-(2′-hydroxy-5′-methacryloxyethylphenyl)-2H-benzotriazole and 2 g ofazobisisobutyronitrile was added dropwise to 370 g of the solventmixture, yielding a solution containing an acrylic polymer having anumber-average molecular weight of 103,000.

Separately, 1.00 mole of γ-aminoethylaminopropyl-trimethoxysilane and2.00 moles of γ-glycidoxypropyl-dimethoxysilane were subjected to aring-opening reaction in the presence of 3.00 moles ofhexamethyldisilazane. The product was further reacted with 2.00 moles ofacetic anhydride to form an adhesion improver. Next, 10 g of a methylisobutyl ketone solution containing 20% of the adhesion improver wasadded to 100 g of the solution prepared above, yielding amoisture-curable, protective layer-forming coating composition solutionR.

Synthesis Example 16

To 100 g of a propylene glycol monomethyl ether acetate solutioncontaining 30% of poly(methyl methacrylate) resin having anumber-average molecular weight of 200,000 were added 3 g of2,4′-dihydroxybenzophenone and 150 g of diacetone alcohol. Theingredients were stirred until dissolved. A thermoplastic, protectivelayer-forming coating composition solution S was prepared.

Coating Method

The transparent resin substrates used included 0.5 mm thickpolycarbonate (PC) and acrylic resin sheets measuring 10×10 cm, and 50μm thick polyethylene terephthalate (PET) films measuring 10×10 cm. Ontoa transparent resin sheet or film whose surface had been cleaned, acoating composition was applied to a predetermined thickness usingeither a bar coater or by dipping.

When a protective coat-forming coating composition solution was appliedalone, a cured coat having a thickness of 2 to 3 μm was formed.

When multiple layers were formed, respective coating solutions wereapplied so as to form a protective layer of 3 to 5 μm thick, a highrefractive index layer of 0.1 to 0.3 μm thick, and a low refractiveindex layer (cured coat of a protective coat-forming coating compositionsolution) of 0.1 to 0.3 μm thick.

Curing Conditions

Heat Curing

The solution was applied, after which the coating was air dried toevaporate off the solvent, then held in a hot air circulation oven at 80to 120° C. for 5 to 30 minutes to effect curing.

UV Curing

The coating was cured by exposing it three times to a dose of 200 mJ/cm²with a high-pressure mercury vapor lamp. In the event multiple layerswere formed, the underlying layer was cured before the overlying layerwas coated and cured.

The following methods were used to measure or evaluate various physicalproperties.

Mar Resistance Test

Test-1

Using a reciprocal scratch tester (KNT Co., Ltd.) equipped with steelwool #0000, the sample was rubbed back and forth with the wool over tencycles under a load of 100 g/cm². The number of streaks was counted.Rating Streaks ⊚ 0 ◯ 1 or 2 Δ 3 to 5 X 6 or more

Test-2

In Test-1, flannel fabric was used instead of the steel wool and movedback and forth 1000 cycles under a load of 1 kg. The number of flaws wascounted. Rating Flaws ◯ no flaw Δ hazed X peeled

Adhesion of Cured Coat

Measured in accordance with JIS K5400. Using a razor blade, the samplewas scored with 11 lines each in the vertical and horizontal directionsat 1 mm intervals, thereby forming a grid of 100 square sections. Acommercial adhesive tape was bonded securely to the scored sample, thenrapidly pulled back at an angle of 90 degrees. Some coating sectionsmight be peeled off together. The number of intact sections (X) isreported as X/100.

Refractive Index

Measured by a prism coupler (Seki Technotron Co., Ltd.)

Antireflection

By visual observation, antireflective property was rated as “◯” for goodand “A” for poor.

Chemical Resistance

A droplet of a chemical fluid was dropped or a chemical fluid wasapplied to a coating, which was allowed to stand over one day. After thechemical fluid was removed, the surface state was visually inspected.The chemical fluids used were 0.1 N NaOH, ethanol, household detergentsMypet® and Magiclean® and skin care creme Nivea® (trade marks are allproducts of Kao Co., Ltd.). Rating State ◯ unchanged Δ marks remained Xcoating dissolved away

Examples 1-3

On an acrylic resin sheet and a PC sheet, each of the protectivecoat-forming coating composition solutions A and B obtained in SynthesisExamples 1 and 2 was applied as a protective layer coating to form asingle layer. The coating properties of these coated sheets wereexamined by the aforementioned tests. The results are shown in Table 1.TABLE 1 Example 1 Example 2 Example 3 Substrate acrylic acrylic PCCoating composition A B A Mar resistance Test-1 ⊚ ⊚ ⊚ Test-2 ◯ ◯ ◯Adhesion (X/100) 100/100 100/100 100/100 Chemical resistance 0.1N NaOH ◯◯ ◯ Mypet ® ◯ ◯ ◯ Nivea ® ◯ ◯ ◯ Magiclean ® ◯ ◯ ◯ Ethanol ◯ ◯ ◯Refractive index 1.399 1.389 1.399

It is seen from Table 1 that the coats obtained from the protectivecoat-forming coating compositions within the scope of the inventionexhibit excellent mar resistance and chemical resistance and have arefractive index of less than 1.400.

Examples 4-8 and Comparative Examples 1-4

On PET films, protective layer-forming coating composition solutions M,P, Q, R and S, high refractive index layer-forming coating compositionsolutions N and K, protective coat-forming coating composition solutionsA-d, B-d, C-d, D-d, E-d, F, G, H and J, prepared in Synthesis Examples 1to 16, were successively applied and cured to form multilayer laminates.The coating properties of these laminates were examined by theaforementioned tests. The results are shown in Table 2. TABLE 2 ExampleComparative Example 4 5 6 7 8 1 2 3 4 Protective layer M P Q R S M M M MHigh refractive index layer K N K N N K K K K Coating composition A-dB-d C-d D-d E-d F G H J Mar Test-1 ⊚ ⊚ ⊚ ⊚ ⊚ ◯ X Δ X resistance Test-2 ◯◯ ◯ ◯ ◯ ◯ Δ ◯ X Adhesion (X/100) 100 100 100 100 100 90 100 100 30Chemical 0.1N NaOH ◯ ◯ ◯ ◯ ◯ X Δ X ◯ resistance Mypet ® ◯ ◯ ◯ ◯ ◯ Δ ◯ Δ◯ Nivea ® ◯ ◯ ◯ ◯ ◯ ◯ ◯ Δ ◯ Magiclean ® ◯ ◯ ◯ ◯ ◯ ◯ ◯ Δ ◯ Ethanol ◯ ◯ ◯◯ ◯ ◯ ◯ Δ ◯ Antireflection ◯ ◯ ◯ ◯ ◯ ◯ Δ ◯ ◯

It is seen from Table 2 that the coats obtained from the protectivecoat-forming coating compositions within the scope of the inventionexhibit excellent mar resistance, chemical resistance andantireflection.

The protective coat-forming coating compositions of the invention formcured coats having excellent chemical resistance and antireflection.

Japanese Patent Application No. 2003-113737 is incorporated herein byreference.

Although some preferred embodiments have been described, manymodifications and variations may be made thereto in light of the aboveteachings. It is therefore to be understood that the invention may bepracticed otherwise than as specifically described without departingfrom the scope of the appended claims.

1. A coated article comprising a transparent substrate and a cured coatformed thereon from a protective coat-forming coating composition,serving as a chemical resistant film, said coating composition primarilycomprising a disilane compound having the formula (A):X_(m)R¹ _(3-m)Si—Y—SiR¹ _(3-m)X_(m)  (A) wherein R¹ is a monovalenthydrocarbon group of 1 to 6 carbon atoms, Y is a divalent organo groupcontaining at least one fluorine atom, X is a hydrolyzable group, and mis 1, 2 or 3, or a (partial) hydrolyzate thereof.
 2. A coated articlecomprising a transparent substrate and a cured coat formed thereon froma protective coat-forming coating composition, serving as anantireflection film, said coating composition primarily comprising adisilane compound having the formula (A):X_(m)R¹ _(3-m)Si—Y—SiR¹ _(3-m)X_(m)  (A) wherein R¹ is a monovalenthydrocarbon group of 1 to 6 carbon atoms, Y is a divalent organo groupcontaining at least one fluorine atom, X is a hydrolyzable group, and mis 1, 2 or 3, or a (partial) hydrolyzate thereof.
 3. A coated articlecomprising a transparent substrate, a layer formed thereon having ahigher refractive index than the substrate, and a cured coat formed on ahigh refractive index layer from a protective coat-forming coatingcomposition, serving as an antireflection film, said coating compositionprimarily comprising a disilane compound having the formula (A):X_(m)R¹ _(3-m)Si—Y—SiR¹ _(3-m)X_(m)  (A) wherein R¹ is a monovalenthydrocarbon group of 1 to 6 carbon atoms, Y is a divalent organo groupcontaining at least one fluorine atom, X is a hydrolyzable group, and mis 1, 2 or 3, or a (partial) hydrolyzate thereof.
 4. The coated articleof claim 3, further comprising a mar resistant protective layer betweenthe substrate and the high refractive index layer.
 5. The coated articleof claim 3, wherein the high refractive index layer comprises a metaloxide sol.
 6. The coated article of claim 5, wherein the metal oxide solcontains at least one element selected from among Ti, Sn, Ce, Al, Zr andIn.
 7. The coated article of claim 3, wherein a coating composition fromwhich the high refractive index layer is formed is thermosetting orphoto-curing.
 8. The coated article of claim 4, wherein a coatingcomposition from which the protective layer is formed is thermosettingor photo-curing.
 9. The coated article of claim 1, wherein saidtransparent substrate comprises an organic resin and/or an inorganicmaterial such as glass or ceramics.
 10. The coated article of claim 1,wherein said transparent substrate comprises a polycarbonate resin,polyalkylene terephthalate resin, cellulose triacetate resin,polystyrene resin or polyolefin resin.
 11. A multilayer laminatecomprising the coated article of claim 1, a tackifier or adhesive layerlying on the transparent substrate side of the coated article, and arelease layer lying thereon.
 12. The multilayer laminate of claim 11,wherein said transparent substrate is a film.
 13. The coated article ofclaim 4, wherein the mar resistant protective layer is (A) a layerprepared by subjecting a radiation-polymerizable composition comprisinga (meth)acrylic functional group-bearing organosilicon compound toradiation polymerization so as to effect curing; (B) a layer prepared bycuring a composition comprising a hydrolyzable silyl group-bearingacrylic polymer; or (C) a layer composed of a thermoplastic acrylicresin containing methyl methacrylate as a major comonomer and having anexcellent heat resistance and a high hardness.
 14. The coated article ofclaim 13, wherein the mar resistant protective layer contains fineparticles of an inorganic oxide and/or a ultraviolet absorber.
 15. Acoated article comprising a transparent substrate and a cured coatformed thereon from a protective coat-forming coating composition ofclaim 1, serving as a chemical resistant film, said coating compositionprimarily comprising a mixture of (i) a disilane compound having theformula (A):X_(m)R¹ _(3-m)Si—Y—SiR¹ _(3-m)X_(m)  (A) wherein R¹ is a monovalenthydrocarbon group of 1 to 6 carbon atoms, Y is a divalent organo groupcontaining at least one fluorine atom, X is a hydrolyzable group, and mis 1, 2 or 3, or a (partial) hydrolyzate thereof and optionally, (ii) afluorinated organo group-containing organosilicon compound having theformula (B):Rf—SiX₃  (B) wherein Rf is a monovalent organo group containing at leastone fluorine atom and X is a hydrolyzable group or a (partial)hydrolyzate thereof, wherein the content of component (i) is 60% byweight to 100% by weight of the mixture.
 16. A coated article comprisinga transparent substrate and a cured coat formed thereon from aprotective coat-forming coating composition of claim 2, serving as anantireflection film, said coating composition primarily comprising amixture of (i) a disilane compound having the formula (A):X_(m)R¹ _(3-m)Si—Y—SiR¹ _(3-m)X_(m)  (A) wherein R¹ is a monovalenthydrocarbon group of 1 to 6 carbon atoms, Y is a divalent organo groupcontaining at least one fluorine atom, X is a hydrolyzable group, and mis 1, 2 or 3, or a (partial) hydrolyzate thereof and optionally, (ii) afluorinated organo group-containing organosilicon compound having theformula (B):Rf—SiX₃  (B) wherein Rf is a monovalent organo group containing at leastone fluorine atom and X is a hydrolyzable group or a (partial)hydrolyzate thereof, wherein the content of component (i) is 60% byweight to 100% by weight of the mixture.
 17. A coated article comprisinga transparent substrate, a layer formed thereon having a higherrefractive index than the substrate, and a cured coat formed on a highrefractive index layer from a protective coat-forming coatingcomposition of claim 3, serving as an antireflection film, said coatingcomposition primarily comprising a mixture of (i) a disilane compoundhaving the formula (A):X_(m)R¹ _(3-m)Si—Y—SiR¹ _(3-m)X_(m)  (A) wherein R¹ is a monovalenthydrocarbon group of 1 to 6 carbon atoms, Y is a divalent organo groupcontaining at least one fluorine atom, X is a hydrolyzable group, and mis 1, 2 or 3, or a (partial) hydrolyzate thereof and optionally, (ii) afluorinated organo group-containing organosilicon compound having theformula (B):Rf—SiX₃  (B) wherein Rf is a monovalent organo group containing at leastone fluorine atom and X is a hydrolyzable group or a (partial)hydrolyzate thereof, wherein the content of component (i) is 60% byweight to 100% by weight of the mixture.
 18. A coated article comprisinga transparent substrate and a cured coat formed thereon from aprotective coat-forming coating composition, serving as a chemicalresistant film, said coating composition primarily comprising aco-hydrolyzate of a mixture of (i) a disilane compound having theformula (A):X_(m)R¹ _(3-m)Si—Y—SiR¹ _(3-m)X_(m)  (A) wherein R¹ is a monovalenthydrocarbon group of 1 to 6 carbon atoms, Y is a divalent organo groupcontaining at least one fluorine atom, X is a hydrolyzable group, and mis 1, 2 or 3, or a (partial) hydrolyzate thereof and (ii) a fluorinatedorgano group-containing organosilicon compound having the formula (B):Rf—SiX₃  (B) wherein Rf is a monovalent organo group containing at leastone fluorine atom and X is a hydrolyzable group or a (partial)hydrolyzate thereof, wherein the content of component (i) is 60% byweight to less than 100% by weight of the mixture.
 19. A coated articlecomprising a transparent substrate and a cured coat formed thereon froma protective coat-forming coating composition, serving as anantireflection film, said coating composition primarily comprising aco-hydrolyzate of a mixture of (i) a disilane compound having theformula (A):X_(m)R¹ _(3-m)Si—Y—SiR¹ _(3-m)X_(m)  (A) wherein R¹ is a monovalenthydrocarbon group of 1 to 6 carbon atoms, Y is a divalent organo groupcontaining at least one fluorine atom, X is a hydrolyzable group, and mis 1, 2 or 3, or a (partial) hydrolyzate thereof and (ii) a fluorinatedorgano group-containing organosilicon compound having the formula (B):Rf—SiX₃  (B) wherein Rf is a monovalent organo group containing at leastone fluorine atom and X is a hydrolyzable group or a (partial)hydrolyzate thereof, wherein the content of component (i) is 60% byweight to less than 100% by weight of the mixture.
 20. A coated articlecomprising a transparent substrate, a layer formed thereon having ahigher refractive index than the substrate, and a cured coat formed on ahigh refractive index layer from a protective coat-forming coatingcomposition, serving as an antireflection film, said coating compositionprimarily comprising a co-hydrolyzate of a mixture of (i) a disilanecompound having the formula (A):X_(m)R¹ _(3-m)Si—Y—SiR¹ _(3-m)X_(m)  (A) wherein R¹ is a monovalenthydrocarbon group of 1 to 6 carbon atoms, Y is a divalent organo groupcontaining at least one fluorine atom, X is a hydrolyzable group, and mis 1, 2 or 3, or a (partial) hydrolyzate thereof and (ii) a fluorinatedorgano group-containing organosilicon compound having the formula (B):Rf—SiX₃  (B) wherein Rf is a monovalent organo group containing at leastone fluorine atom and X is a hydrolyzable group or a (partial)hydrolyzate thereof, wherein the content of component (i) is 60% byweight to less than 100% by weight of the mixture.
 21. The coatedarticle of claim 20, further comprising a mar resistant protective layerbetween the substrate and the high refractive index layer.
 22. Thecoated article of claim 20, wherein the high refractive index layercomprises a metal oxide sol.
 23. The coated article of claim 22, whereinthe metal oxide sol contains at least one element selected from amongTi, Sn, Ce, Al, Zr and In.
 24. The coated article of claim 20, wherein acoating composition from which the high refractive index layer is formedis thermosetting or photo-curing.
 25. The coated article of claim 21,wherein a coating composition from which the protective layer is formedis thermosetting or photo-curing.
 26. The coated article of claim 18,wherein said transparent substrate comprises an organic resin and/or aninorganic material such as glass or ceramics.
 27. The coated article ofclaim 18, wherein said transparent substrate comprises a polycarbonateresin, polyalkylene terephthalate resin, cellulose triacetate resin,polystyrene resin or polyolefin resin.
 28. A multilayer laminatecomprising the coated article of claim 18, a tackifier or adhesive layerlying on the transparent substrate side of the coated article, and arelease layer lying thereon.
 29. The multilayer laminate of claim 28,wherein said transparent substrate is a film.
 30. The coated article ofclaim 21, wherein the mar resistant protective layer is (A) a layerprepared by subjecting a radiation-polymerizable composition comprisinga (meth)acrylic functional group-bearing organosilicon compound toradiation polymerization so as to effect curing; (B) a layer prepared bycuring a composition comprising a hydrolyzable silyl group-bearingacrylic polymer; or (C) a layer composed of a thermoplastic acrylicresin containing methyl methacrylate as a major comonomer and having anexcellent heat resistance and a high hardness.
 31. The coated article ofclaim 30, wherein the mar resistant protective layer contains fineparticles of an inorganic oxide and/or a ultraviolet absorber.